The bill has been praised by law enforcement and has bipartisan support, even as civil liberties groups have raised privacy concerns and some terror experts say it won't deter bad behavior.

Schumer, a Democrat, and Cornyn, a Republican, are hoping to schedule hearings on the bill through the Judiciary Committee. Schumer has urged Attorney General Eric Holder to back the measure.

Prepaid phones can be a lifeline for people with limited incomes or poor credit, allowing them to purchase a device and a limited amount of calling time without commiting to a costly contract. Phone companies sold $16 billion worth of prepaid cell phones last year, and the devices are hugely popular in both the U.S. and countries around the world.

But since the phones can be purchased anonymously and are thrown away after use, they've long been a favored tool of drug dealers, gang members and even white-collar criminals looking to cover their tracks.

In recent years, such phones also have been linked to suspected terror activity -- including that by Faisal Shahzad, the Pakistani-American accused of plotting to bomb Times Square. Law enforcement officials said Shahzad had used a prepaid cell phone to purchase a car in which to hide the bomb and to communicate with co-conspirators in Pakistan.

A handful of states and several countries require registration to purchase a prepaid cell phone. In an interview, Schumer said the Shahzad case, combined with the growing use of prepaid cell phones in criminal cases, had persuaded him that federal regulation was needed.

"If law enforcement has a legitimate need to surveil, let them surveil," Schumer told The Associated Press, adding, "you can make sure privacy is protected."

That's not a view necessarily shared by civil liberties groups and other advocates of digital privacy, who say they have both legal and practical objections.

"The Supreme Court has always upheld the principle that you have the right to speak anonymously -- that the decision to identify yourself as a speaker is an aspect of speech itself," said Lee Tien, a senior staff attorney with the Electronic Frontier Foundation.

Tien also noted that many people, especially younger ones, regularly swap phones and SIM cards and buy used cell phones, further blurring the identity of the phones' users and owners.

"For a variety of reasons, this doesn't sound like a `get off the ground' kind of idea," he said.

Schumer disagreed, saying the identity of prepaid cell purchasers would be kept private by phone companies in the same way the identities of regular cell and landline phone owners are protected.

So far, no major phone company has objected to the legislation and some say they fully embrace it.

"We are living in a time when unfortunately our public safety rquires small gives by everyone," Verizon spokesman Jeffrey Nelson said.

Still, Jack Cloonan, a former FBI special agent and counterterrorism specialist, said the legislation would not prevent terror plotters from getting access to the communication tools they need.

"The bottom line is the terrorists, whether they're the Pakistani Taliban or whether they're closely aligned with al-Qaida, use technology to their advantage," Cloonan said. "They try to stay ahead of us and we're always playing catch up."